tharaldsen



F. THARALDSEN PROCESS FOR ELECTROTHERMIC PRODUCTION OF ZINC I Filed may 25, 1922 tion of the charge it and also to prevent molten rrmr 'rnianannsnn, or characterize, NORWAY.

Application filed. Ioiey 255,

To all whom it may concern I Be it lmown that I, Fine Tnsnannsnn, a citizen of Norway, residing at Christ-iania, Norway, have invented certain new and useful Improvements in Processes for Electra thermic Production of Zinc, for which. l have filed application for patent in Norway June 27, 1918, and of which the following is a specification.

The object of the invention is to provide an improved process of production of zinc in electric resistance furnaces.

In the electrothcrmic production of zinc in resistance furnaces it has been proposed to arrange the charge consisting of zinc bearing materials and reducing agents as an even horizontal layer on a stratum of coke. which latter serves as heating resist ance. of heat to the charge is secured. and the electric ctficiency of the furnace is very high. The layer of coke serves as heating resistance and at the same time it prevents the charge from getting in immediate contact with the bottom of the furnace and sticking to it in baking.

According to the present invention the zinc containing charge proper is used 'as heating resistance. By convenient composihas proved possible to obtain sufficient conductivity in the charge slag from getting in touch with the hearth of the furnace. Generally speaking the invention can be carried out by usinq a sutlicient surplus of reducing agent in t e charge. However the invention more specially aims at using pure or nearly pure oxide of sine as raw material. A charge consisting of zinc oxide am reducing agent has proved serviceable as heating resistance even without contain ing any considerable surplus of reductive and the detrimental effect of molten slag upon the bottom of the furnace does not make itself felt as in this case such masses are not formed to any appreciable extent, the whole charge being vclatilized except a trifling residue of excess carbon, which how ever does no harm. a

A charge of zinc oxide and carbon has a very considerable conductivity owing to the finely divided state of the oxide and because of the absence of rocky constituents.

In order to secure a uniform heating' of the charge notwithstanding that its conduc tivlty is greater 111 the hot state than when in this way a very uniform transfer which a charge is placed outside hereby declare that what.

9293. fseriai 13in. 563,61

relatively cold, the invention provides preheating of the charge before it arrives in the zone of the furnace. where the resistance heating occurs. This preheatingis effected for'instance in the manner, that th charge, which is introduced into the once in the shape of a uniform thin layer, is first exposed to radiation from an electric arc, and then when it has assumed a. convenient temperature and conductivity it is subjected to direct passage of the current.

The type of furnace used for carrying out the invention is shown on the accompanying drawings in which- Figure l a transverse section on the plane indicated by the line ll of Fig ure 2.

Figure 2 is a longitudinal section on the plane indicated by the line of Figural.

The furnace has a .iuovahle hearth on i the. furnace chamber, and said hearth conveys the charge into the furnace, thereby distributing the charge in the form or a horizontal layer, which is subjected to reduction suecessivcly as it advances through the furnace chamber.

The arrangement of zont-al cause it the charge as ahorilayer is of special importance, hesecures one and the same section. for

scqueutly a. uniform resistance. ing of the charge is then uniform the hearth. 1

In the tgirnace shown 'injthe electric current is supplied by means of the electrodes A. to charge- E. on the hearth {7. The increment of the hearth is supposed to be lroin the left to the right. T he preheating of the char "2 is efiected by means of an electric are he tween the electrodes 1). The zinc vapors evolved in the furnace chamber escape through the outlet E,

'aving; now fully described my invention and the manner in which it. is perliornied, 1i

claim is:

1. fine process of electrothermically pro- (lacing zinc consisting in first heating a. charge of zinc oxide and carbon by radiation from an electric arc, and then subjectinc the charge to the direct passage of'the electric current therethrough.

2. The process of electrothermirallyp11 duciug zinc cc istiug in first preparing a charge of zinc oxide and carbon in a layer all over drawing the uniformly distrihutetl' ESE m (if uniform thickness and substantially unifm'znelectricnl resistance at all points moving such charge through a furnace, and heat1n; such charge whlle moving, first bv radiation from an electric arc, and then subjecting such charge to the direct passage of w the electric current therethrough.

'In testimony whereof I aflix my signature in presence of two witnesses.

FILIP THARALDSEN. Vitnesses:

P. Bnomn, H. Fnnrmss. 

